An industry group representing Canadian chief executives is calling on Boeing Co. to scrap its trade challenge against Montreal-based Bombardier Inc.

“Boeing’s petition for duties on Bombardier aircraft is baseless and should be immediately withdrawn,” John Manley, president of the Business Council of Canada, said in a statement released Sunday. “Canada must stand up to this unprecedented attack on our aerospace industry and the thousands of men and women it employs.”

Manley is weighing in ahead of an anticipated ruling on preliminary duties due Tuesday on the complaint from Chicago-based Boeing. The dispute threatens to divide Canadian industry given the complex supply chains of both firms. Bombardier is based in Canada, though Boeing drew $2.2 billion in revenue from the country in 2016, compared with $1.3 billion for Bombardier, data compiled by Bloomberg show.

Canadian Prime Minister Justin Trudeau and U.K. Prime Minister Theresa May have appealed to U.S. President Donald Trump to intervene in the case. Boeing has accused Bombardier of using government subsidies to sell its C Series passenger jets at low prices.

Trudeau has also said Canada won’t proceed with an acquisition of Boeing F-18 Super Hornets so long as the firm is targeting its Canadian rival.

Boeing has given no indication it will back down, firing back earlier this month when Trudeau took aim at them by saying Bombardier’s U.S. sales are “a classic case of dumping, made possible by a major injection of public funds.”

Bombardier says Boeing has similar “launch pricing” for its new planes as Bombardier does for its new C Series. “Boeing’s self-serving actions threaten thousands of aerospace jobs around the world,” Bombardier said in its own statement earlier this month.